It is known to operate hand tools or work devices driven by electric motors independently from an electrical supply network and to furnish the hand tools and work devices with batteries and especially with rechargeable batteries. However, the power and the operating lives of such battery operated tools and devices, are comparatively small, since the batteries interfere with the capability of handling of the tool or the device are too large, or are too heavy. Usually, such hand tools or work devices have low power drives and require frequent recharging of the batteries.
On the other hand supply apparatus comprising rechargeable electrical energy sources are known for boats to power the electrical board system. Such electrical supply apparatus are connected to the board grid by plugs and sockets. These known supply apparatus are less suitable for electrically operated hand tools or work devices, since the plug connection can easily unplug upon movement of the hand tool or the work device. In addition, the supply apparatus has to be picked up again and again corresponding to the advance in the work and has to be carried after the hand tool and work device, respectively.